1. Project Introduction

2. Research Question

3. Dataset Information

4. Exploratory Analysis

4.1 Global Data

This is data from entire globe.

4.2 NPSG Data

Distribution of Samples

Samples within the NPSG.

Distribution of Plastics Densities

Samples of different density classes.

Other variables: does the amount of plastic differ with time?

Plastics over Time

Plastics over Time

At first glance, there appears to be an upward trend.

5. Exploratory Analysis

5.1 Variability in sampling methods

Table 1. Occurrences of Various Sampling Methods within Global Dataset
Method Number of Samples
Aluminum bucket 57
AVANI net 18
CTD rosette sampler 6
Day grab 17
Grab sample 1116
Hand picking 5810
Intake seawater pump 131
Manta net 861
Megacorer 90
Metal spoon 76
Neuston net 7207
Petite Ponar benthic grab 36
Plankton net 74
PVC cylinder 370
Remotely operated vehicle 40
Shipek grab sampler 9
Stainless steel spoon 50
Van Dorn sampler 181
Van Veen grab sampler 7
Sampling Method

Sampling Method

Measurements take by each sampling method.

5.2 Plastics and time

Table 2. Generalized Linear Model Analysis
Analysis P-Value
Linear Regression 1.284e-05
Table 3. AIC Analysis, formula = Measurement ~ Year + Month + Latitude + Longitude
Variable AIC
- Longitude 1069.2
no change 1070.6
- Latitude 1071.3
- Month 1076.2
- Year 1090.5

P value is less than significance level of 0.05. AIC suggests Month, Year, and Latitude are explanatory variables.

5.3 Time series

Figure 3. Decomposition of time series

Figure 3. Decomposition of time series

Seasonality removed

Seasonality removed

Table 4. Trend Analyses
Analysis 2-sided P-Value
Seasonal Mann-Kendall 0.11049
Non-Seasonal Mann-Kendall 0.069721

Interpolated values across the years. Time series analysis, there does seem to be seasonality. The trend has a stronger increase in later years.

6. Summary and Conclusions

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